hexa = [ 1, 6, 15, 28, 45, 66, 91, 120, 153, 190, 231, 276, 325, 378, 435, 496, 561, 630, 703, 780, 861, 946, 1035, 1128, 1225, 1326, 1431, 1540, 1653, 1770, 1891, 2016, 2145, 2278, 2415, 2556, 2701, 2850, 3003, 3160, 3321, 3486, 3655, 3828, 4005, 4186, 4371, 4560, 4753, 4950, 5151, 5356, 5565, 5778, 5995, 6216, 6441, 6670, 6903, 7140, 7381, 7626, 7875, 8128, 8385, 8646, 8911, 9180, 9453, 9730 ]
